Aristotle "Ari" Mendoza
Ari is one of the two main characters in the novel. He is fifteen years old, bored, lonely and friendless. He lives with his loving parents but cannot connect with them because the Mendozas are not a family who show affection very much. They are also not big talkers when it comes to their emotions. Ari has two sisters who already left home and an older brother in jail for murder. He wants to know about his brother and is frustrated that he is never spoken of. His family acts as if his brother is dead.
Ari is looking to find his place in the world, and to understand the secrets of the universe, but his sexual orientation is not one of these things. It doesn't occur to him that he might be gay. He is attracted to a girl named Illeana, whom he kisses at a party, and seems, in general, to be attracted to girls. It simply isn't an issue that he thinks about.
Ari becomes gradually more angry after his accident. This is most likely because he has realized he is attracted to Dante but does not want to admit it to himself. He is supportive of Dante when he comes out to him but uneasy about being hit on by his friend. He tells Dante he feels nothing when they kiss, but this is not true. Ari is in a state of self-denial, and finally realizes at the end of the novel that he has been in love with Dante all along.
Dante Quintana
Dante differs from Ari in that he knows he is gay and although he questions whether he prefers kissing boys or kissing girls, he in his heart already knows the answer. Dante is in love with Ari but unlike his friend does not try to deny this. He tries to tell Ari a couple of times, but it is awkward and he ends up feeling rejected.
Dante is also different from Ari in general demeanor and character. He is confident and talented. He is a very good swimmer, an academic and interested in the classics of art and literature. He is very popular. He lives with his parents, they all demonstrate their love and affection, and they have an open and easy relationship. He is concerned that he will be letting them down when he comes out to them and has no idea they have already figured out that he is in love with Ari.
Bernardo Mendoza
Considering that we never see Bernardo, who is Ari's brother, in person, he is a surprisingly important character in the novel. His absence is felt strongly by Ari who feels that he is missing out on an older brother and also wants to know the full story behind his incarceration. Bernardo was already venturing into questionable behavior; he was involved with people his mother did not care for and hired prostitutes. He is violent and a bigot. He is in prison for killing a trans person with his bare hands.
Daniel
Daniel is Dante's first real boyfriend. They meet at the pharmacy where they both work. While kissing Daniel in an alley behind the pharmacy, Dante is jumped and beaten up because of his sexual orientation. Daniel runs off to safety while this occurs, and although he comes diligently to visit Dante whilst he is recovering, Ari views this as a sign that he is not committed enough to Dante (after all, Ari almost got himself killed making sure that Dante was safe). Daniel is in a way a substitute for Ari in Dante's eyes, and is taking his mind away from the real love of his life.
Mrs. Mendoza
Mrs. Mendoza is Ari's mother. She loves her son very much, but worries that he is going to turn out like his brother. She does not like the way in which her husband and son refuse to express themselves or their feelings, but she acts in exactly the same way. When Bernardo was on trial and found guilty of murder, she had a mental breakdown and was unable to take care of Ari. She believes that the only way for the family to move forward is to start talking about their feelings. She is a tolerant woman who stood by her sister even when the rest of her family had ostracized her for her sexual orientation. She is very accepting of her son's orientation and love for Dante.
Mr. Mendoza
Mr. Mendoza is Ari's father. He is a kind man but very remote emotionally. He was deeply affected by his experiences serving in Vietnam in the war but never talks about them. This makes him rather unreachable. His habit of not expressing his feelings has been passed down to his son. At bottom, though, Mr. Mendoza is a strong man and a decent one. He is thoroughly supportive of Aunt Ophelia, and thoroughly supportive of his son's feelings for Dante.
Mrs. Quintana
Mrs. Quintana is the first person other than Dante to realize that her son is in love with Ari. She does her best to encourage this and reaches out to the Mendozas so that they can become more connected to each other. She also begins the dialogue between the parents regarding their sons.
Mr. Quintana
Dante's father is far more emotionally available than Ari's. He does not mind at all expressing love and affection and his family all get along easily and with obvious love for each other. He knows his son well and has made sure to do so. He knows that Dante is gay and realizes he loves Ari by the way that he looks at him.
Aunt Ophelia
Ari's Aunt Ophelia dies from a very bad stroke during the course of the narrative. Ari and his parents are the only immediate family members who attend her funeral. This is because she was ostracized by her family for being gay and living as a lesbian with her partner. She was clearly a loving and giving woman because she opened her home to Ari when her sister (his mother) had a mental breakdown. She raised Ari when he was very young.
Gina and Susie
Gina and Susie are friends Ari and Dante meet at school. Ari spends most of his time with them when Dante is living in Chicago during the school year. They most probably are attracted to Ari; as female readers know, when a girl is argumentative and starts to bicker with you, she usually really likes you. Both girls include Ari in their socializing and create a social circle for him that he did not have previously.
Ileana
Ileana is the first girl Ari ever kisses. He dreams of the kiss from the beginning of the school year and finally receives it at a party just before the start of summer. She is not quite so obsessed as he is, but she likes Ari. She also admits to him that their kiss is as far as it goes; she has a boyfriend, and he's in a gang. We later learn she gets pregnant and drops out of school.
